1. Field of the Invention
The present invention relates to connectors used for electrically connecting such as electronic devices and contact modules provided in the connectors.
2. Description of the Related Art
Connectors are used for electrically connecting a plurality of electronic devices or electronic components.
The connectors are classified into various types according to the shapes and the like.
For example, according to the mounting patterns, the connectors can be classified as connectors for boards connected to boards, LSI sockets connected to LSIs, and relay connectors used for connecting cables to cables.
Among the above described various connectors, the connectors for boards, for example, can be further divided into two major categories: the card edge type and the two piece type.
Card edge type connectors shown in FIGS. 1 and 2 are used for connection between a mother board 1 and a daughter card 2. The card edge type connectors are constructed such that a pair of contacts (terminals) 4 hold tight pads 3 provided on patterns (not shown) formed on both sides of the daughter card 2. In other words, the patterns of the daughter card 2 are used as the insertion side. A connector 5a in FIG. 1 is a throughhole mounting type connector that is mounted on the mother board 1 by inserting, soldering and fixing one end of each of the contacts 4 in a throughhole (not shown) formed on the mother board 1. A connector 5b in FIG. 2 is a surface mounting type connector that is mounted on the mother board 1 by soldering and fixing one end of each of the contacts 4 to a pad 6 formed on the mother board 1.
A two piece type connector 5c shown in FIG. 3 is used such that two connectors 5c-1 and 5c-2, a receiving connector and an inserting connector, are mounted on two boards 1 and 7, respectively, and the two connectors 5c-1 and 5c-2 are made to fit.
As mentioned above, there are differences in the connector shapes depending on the mounting patterns. However, each of the above-described connectors for boards, LSI sockets and relay connectors is constructed such that a lot of contacts formed into pin shapes or tongue shapes using a metal material are accommodated in a housing (designated by reference numeral 8 in FIGS. 1 through 3) formed by insulating resin.
If the contacts are of press fit types and have pin-like shapes, for example, the contacts are formed by notching, stamp-out pressing, bending, or form pressing a flat metal material. In addition, if the contacts are formed into a tongue shape, similarly, a flat metal material is notched or stamp-out pressed so as to obtain a lot of contacts. Normally, spring characteristics are given to the contacts by using a plate made of a metal material. Also, the contacts are plated with gold after performing base plating thereon so as to obtain good electric conductivity.
By the way, it is required that the connectors possess predetermined characteristics as connecting components as well as electrical characteristics that will be described later.
That is, when mounting the connector to a board or the like, it is preferable that force required for connecting contacts of the connector to such as electrodes of the board, in other words, force required for inserting the connector to a connecting hole or the like of the board, be small. Further, it is necessary that the contacts positively establish contact with such as electrodes of the board after the insertion. Thus, the so-called LIF (Low Insertion Force) structure is used in which spring characteristics are given to the contacts so that great contact force is exerted after the insertion of the contact with a small contact force.
On the other hand, at the insertion of the contact, it is not preferable that the contacts be worn or damaged such that the contact slidably contact such as the electrode. For this reason, the so-called ZIF (Zero Insertion Force) structure is also used in which the contacts and such as electrodes are maintained in a non-contact state and the contacts do not slidably contact such as electrode until the completion of the connection (insertion). Additionally, from these points of view, various shapes and materials of the contacts, various methods for surface treatment and the like are developed.
Regarding the connector, in addition to the above-described specific characteristics, similar to electric components such as a distributing board, a smaller connector, higher-density (narrower pitch) mounting of the contacts, speeding up of transmission rate, that is, improvement of the transmission rate and noise reduction by controlling such as crosstalk are always required.
A conventional connector, however, is formed into a pin shape and the like as described above. Thus, it is reasonable to say that there is a limit to the smaller connector or the higher-density mounting of the contacts. For example, as for the higher-density mounting of the contacts, it is difficult to make the pitch between the contacts equal to or less than 0.2-0.3 mm.
Additionally, since the conventional connector is formed with a three dimensional structure as mentioned above, the conventional connector is designed and manufactured by simulation through a three dimensional CAD or CAE such that the electric characteristics meet a predetermined specification. However, since the shape is complex, it is difficult to control the variation of the characteristic impedance to fall within a range of xc2x110%. Hence, it is difficult to eliminate noise due to impedance mismatching.
It is a general object of the present invention to provide an improved and useful contact module and connector having the contact module in which the above-mentioned problems are eliminated.
It is another and more specific object of the present invention to provide a contact module and connector having the contact module that can realize a smaller apparatus (connector) and higher-density mounting of the contacts to be mounted and perform impedance matching with good accuracy.
In order to achieve the above-mentioned objects, according to one aspect of the present invention, there is provided a contact module that includes: a strip base; a plurality of first protrusions continuously extending from a first end of the base and including the same materials as the base, said first protrusions each having a first contact portion and having spring characteristics at least in a part including said first contact portion; and a plurality of second protrusions continuously extending from a second end of the base and including the same material as the base, said second protrusions each having a second contact portion and having spring characteristics at least in a part including said second contact portion, the second end being opposite to the first end; wherein said base comprises a sheet made of a metal material, an insulating film formed on at least one side of said sheet, and a film including a noble metal material formed on the insulating film, wherein said film forming said first and second contact portions and circuit patterns, said circuit patterns being formed between the first and second contact portions; wherein the first and second contact portions and the circuit patterns integrally form a plurality of contacts, said contacts each comprising one of the first contact portions, a corresponding one of the second contact portions, and the circuit pattern therebetween.
Also, according to another aspect of the present invention, there is provided a connector including: a connector body; and at least one pair of the above-described contact modules provided in the connector body in a mutually opposing manner, the connector body including a pair of press members pressing the contact portions backward and forward so as to change the distance between the opposing first contact portions of the pair of the contact modules.
Here, the circuit patterns includes one of wiring patterns and wires according to specific embodiments. In addition, a material other than a noble metal material, that is, a base metal material, is not excluded for the construction material of the contact portions (contact points) and circuit patterns. However, a noble metal material is preferable for the construction material of the contact portions and circuit patterns in view of obtaining contacts with good mechanical characteristics, such as good abrasion resistance, hostile-environment resistance, and corrosion resistance. In this case, the noble metal material may be one kind of noble metal or several kinds of noble metals. Also, the insulating film, contact portions and circuit patterns may be formed on only one side of the sheet or both sides of the sheet.
Accordingly, it is possible to form thin contacts and to arrange a large number of the contacts finely with a narrow pitch. Hence, it is possible to realize a smaller connector and higher-density mounting of the contacts.
In addition, since the contacts are formed by the thin film-like contact portions and circuit patterns, it is possible to perform impedance matching with good accuracy.
Further, the circuit patterns may be covered with the insulating film with only the contact portions exposed. Thus, compared with a case where the circuit patterns are not covered with the insulating film, when using the connector in which the contact modules are provided, it is possible to prevent such as disconnection due to abrasion and damage even if the circuit patterns of the contacts contact another member, such as a board.
Moreover, by making the sheet including a metal material function as a ground layer, a micro strip line structure can be achieved. Thus, crosstalk and noise are reduced.
Furthermore, in a case of a conventional connector having a structure where a plurality of contacts are arranged, in a state where the connector is mounted to such as a board, it is difficult to avoid occurrence of differences in transmission distances (wiring lengths) of wiring patterns among the contacts when the contacts are connected to the wiring patterns on the board. This leads to a problem especially in a case of balanced transmission, for example. On the other hand, according to the present invention, it is possible to improve this problem by performing an adjustment in advance that provides differences in the pattern lengths of the circuit patterns.
In addition, it is possible to easily give spring characteristics to the sheet made of a metal material. Thus, it is possible to insert the contacts into a mating member by bending the contacts and to obtain contact force through restoring force of the contacts after the insertion.
Additionally, if the adjacent contacts (circuit patterns) are configured to function as a pair of signal lines for balanced transmission, it is possible to preferably reduce crosstalk as in the so-called edge couple in a circuit board. Also, signal coupling can be made as firm as in a circuit board.
Further, the contacts may include a ground contact that functions as a ground line. Also, the ground contact may include in the insulating film at least one slit that extends in the width direction of the ground contact and is arranged in the longitudinal direction of the ground contact so as to expose the sheet from the slit and make the circuit pattern contact the sheet via the slit.
Also, the ground contact may include a long groove extending in the longitudinal direction of the ground contact so as to expose the sheet from the slit and make the circuit pattern contact the sheet via the long groove.
Accordingly, it is possible to make a more positive ground.
In addition, each of the first and second contact portions may be biforked.
Accordingly, when connecting the connector in which the contact modules are provided to another electric component or the like, it is possible to more positively obtain continuity (connection).
Furthermore, it is possible to easily adjust contact force of the contacts by the press members.
In this case, the pair of the press members may each include: a slider-member provided on a back surface side of a corresponding one of the contact modules, catching ends of the first protrusions of the corresponding contact module, and being capable of sliding so as to vary the distance between the opposing first contact portions; and a fitting member mounted between the slider member and the connector body after the first board is inserted between the pair of the contact modules so as to slide the slider member.
In such a case, it is possible to realize the ZIF (Zero Insertion Force) structure by inserting the board in a state where the pair of the slider members are slid and opened so that the distance between the facing contact portions (contacts) becomes greater than the thickness of the board and, after the board is held, mounting the fitting members and sliding the slider members so as to press the contact portions and make the contact portions contact the board.
In addition, the pair of the press members may each include: a slider member provided on a back surface side of a corresponding one of the contact modules, catching ends of the first protrusions of the corresponding contact module, and being capable of sliding so as to vary the distance between the opposing first contact portions; an elastic member installed between a back surface of the slider member and an inner wall of the connector body and urging the slider member to slide; and a fitting member mounted between the slider member and the connector body after the first board is inserted between the pair of the contact modules so as to slide the slider member.
In such a case, the LIF (Low Insertion Force) structure is realized by adjusting the urging force of the elastic members to satisfy a predetermined condition, inserting the board while bringing the board into light contact with the contact portions in a state where the distance between the facing contact portions (contacts) is made approximately the same as or slightly smaller than the thickness of the board, and after the board is held, mounting the fitting members and further sliding the sliding members so as to further press the contact portions. Also, when inserting the board between the pair of the contacts, the contact portions are in slight sliding contact with the board. Hence, it is possible to clean the contact portions and the surfaces of the board.
Further, in each of the contact modules, the first protrusions are projected toward the insertion position of the first board, a circuit pattern side of the contact module from the first contact portions is fixed to the connector body, and top sides of the first protrusions, opposite to the circuit pattern side, are caught by a concave part formed in the slider member.
In such a case, the top sides of the contacts can be displaced in the concave parts. Thus, compared with a case where the top sides of the contacts are fixed to the connector body, it is possible to let excessive force applied to the contacts dissipate by the displacement of the top sides of the contacts. Accordingly, it is possible to easily obtain just enough contact force at the insertion of the board.
Additionally, in each of the contact modules, the second protrusions are bent and formed into substantially L-shapes, the corners of the L-shaped second protrusions are connected, as the second contact portions, to terminals formed on the second board to which principal surface the first board is arranged perpendicularly, a circuit pattern side of the contact modules from the second contact portions are fixed to the connector body, and top sides of the second protrusions, opposite to the circuit pattern side, are caught by a concave part formed in the connector body.
In such a case, the top sides of the contacts can be displaced in the concave parts. Thus, compared with a case where the top sides of the contacts are fixed to the connector body, it is possible to let excessive force applied to the contacts dissipate by the displacement of the top sides of the contacts. Accordingly, it is possible to easily obtain just enough contact force at the insertion of the board.
Additionally, in the second protrusions of the contact module, parts including the respective second contact portions may be formed into pin shapes so as to be put through throughholes formed in the second board so that the first board is fixed to the second board to which principal surface the first board is arranged perpendicular.
In such a case, it is possible to positively connect the contacts (connector) to another (second) board.
Moreover, the pair of the contact modules may hold the first and second boards between the first and second contact portions, respectively, so as to connect the first and second boards in a horizontal direction.
Such a structure is ideal since it is not necessary to use two connectors (two piece type connector).
Furthermore, in this case, a plurality of pairs of the contact modules may be provided in the connector body in a mutually opposing manner such that at least one of the first and second contact portions are arranged along an insertion direction of at least one of the first and second boards.
Such a structure is ideal for performing connection with a board where high-density wiring patterns are formed and terminals (pads) connected to the wiring patterns are arranged alternately in a hound""s tooth pattern.
Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the following drawings.